Graphene is a material formed of hexagonally attached carbon atoms into a two-dimensional planar structure having a honeycomb shape, and it is very thin and transparent, and has high electrical conductivity. Many attempts have been made to apply graphene to a transparent display or a flexible display by using such properties of graphene. In recent years, many attempts have been actively made to synthesize large-area graphene.
Graphene can be prepared by chemically exfoliating a graphite or can be synthesized by a chemical vapor deposition method using a catalyst metal. Further, graphene can be formed or transferred onto a desired substrate and then used for various purposes. By way of example, as a method for transferring graphene synthesized on a surface of a catalyst metal by a chemical vapor deposition method onto a substrate, there has been mainly used a method in which a thermal-release tape is attached to the graphene, the catalyst metal is removed by etching, and then, heat is applied to the thermal-release tape, so that the graphene is transferred onto a substrate film.
However, in this transferring method of graphene, the graphene may be damaged by heat while the thermal-release tape is separated by heating. Further, while the graphene is attached to and separated from the thermal-release tape, the graphene may be mechanically damaged such as being crumpled or destroyed.
Therefore, various transferring methods of graphene have been studied in order to solve such problems. For example, Korean Patent Laid-open Publication No. 2011-0137564 discloses a transferring method of graphene using a hydrophilic oxide layer and water vapor. However, a method for easily transferring graphene or high-quality large-area graphene at low cost has not yet been developed.